Control for pressing machines



Sept. 5, 1939. 5 5 BALDWIN r AL 2,171,529

CONTROL FOR PRESSING MACHINES Filed Dec. 6; 1937 2 Sheets-Sheet 1 FIG-l I INVENTOR 34 z? GEORGE s. BALDWIN wggum s. MAU

ATTORNEY? p 5, 1939- G. s. BALDWIN ET AL 2,171,529

CONTROL FOR PRESSING MACHINES Filed Dec. 6, 1957 2 Sheets-Sheet 2 FIG:- 7

F IG."8

INVENTOR GEORGE S. BALDWIN WIIEIVIAM G. MAU

ATTORNEYS Patented Sept. 5, 1939 UNl'l'il STATES CONTROL FOR PRESSING MACHINES George S. Baldwin, Cleveland Heights, and William G. Man, Cleveland, Ohio, assignors to The American Laundry Machinery Company, Norwood, Ohio, a corporation of Ohio Application December 6, 1937, Serial No. 178,210

6 Claims.

shine.

The invention comprises an improved safety two-hand control wherein toggles connected to opposite ends of an equalizer bar are moved simultaneously to actuate the valve to fluid supply position. and wherein the parts are so constructed and arranged that a rigid valve rigidly mounted is maintained in an efficient fluid supply position by movement of both toggles over dead-center to a locked position. The invention involves parts so arranged that without any springs or yielding parts whatsoever, the valve is moved to supply position and there maintained to hold the press closed.

Other novel features of our invention will appear from the accompanying specification and drawings and the essential features will be set iorth in the claims.

In the drawings, Fig. 1 shows an end elevation of a pressing machine with our improved control mechanism shown diagrammatically in corresponding position; Flg. 2 is a similar view showing the press parts in full lines in a safe-closed position and in broken lines in a fully closed position, the control mechanism being shown diagrammatically corresponding to the full line position of the press parts; Fig. 3 is a view in elevation of the stop member with the control manuals in the position of Fig. 2; Figs. 4, 5 and 6 are views of the control mechanism of Fig. 2 in progressive positions as they are moved to finally attain in Fig. 6 the position corresponding to the fully closed position of the press parts; while Figs. 7 and 8 show the position of the manuals relative to the stop means corresponding respectively to the position or the controls in Figs. 4 and 6.

Our invention is illustrated as applied to a pressing machine having a frame it supporting a pressing bed ii and also pivotally supporting a lever it on which is mounted a pressing head i3 movable into and out of engagement with the bed ill by oscillation of lever 52 under the infiuence of toggle it and the cylinder and piston motor it connected therewith. A spring it normally returns the head to open position.

Fluid is supplied to motor i5 through conduit ii and valve casing Hi.

This casing houses a a ball valve.

Exhaust port I81) is normally open lPATENT OFFICE but may be closed by a shoulder on the valve stem 180. It will be understood that the valve is rigidly mounted on the frame Ill and that there is no give in the parts, that is to say, when the valve is closed the shoulder on iSc firmly en- 5 gages the exhaust port i819, there being no necessity for yieldable gaskets or anything of the sort at this point. Valve stem $80 is engageable by a pin l9 pivotally mounted centrally of the equalizer bar 2%. Pin i9 is guided on the frame 10 for reciprocating movement. To opposite ends of bar 20 are pivotally connected toggles 2i and 22 respectively. Each toggle comprises a link 2 la, 22a and an arm of a bell-crank-like manual 23 and 25. These manuals are pivoted to the frame at 25 and these pivots are fixed relative to valve it so that there is no relative movement between the parts.

A stop member 26 is pivotally mounted on the frame and normally lies between the manuals in the position of Fig. 1 under the influence of rod ill and spring 28. Rod 2'! passes through bracket Ma on toggle it and carries collars Bio and 21b. The collar 21b is preferably threaded on rod 27 for adjustment, as will later appear. The stop 2S normally prevents movement of the manuals beyond a certain point until the press is safely closed, at which time bracket Ma engages collar 2% and rotates the stop downwardly out of position between the manuals. A fixed stop 2Q on 30 the frame limits movement of the manuas in one direction and stop means 3:; rigid with one or both of the manuals performs a limiting function as will hereinafter appear. at will be understood that while stop is shown connected 35 with manual 23, part of this strut might be connected with manual 24.

With the parts in the position of Fig. l, the operator arranges the work on the pressing bed II and moves manuals 23 and 24 to the position of Fig. 2. If either manual is moved alone it is suificient only to take up the gap between pin it and valve stem We and insufiicient to move the valve to fluid supply position. When both manuals are actuated simultaneously, fiuid is supplied from conduit 3i through valve casing i8 and conduit ii to motor l5 so as to cause the press to close. In this condition of the parts if either of the manuals is released its associate toggle will break outwardly permitting the valves in casing it to return to fluid cut-off and exhaust position. This is due to the effect of the pressure fluid supply against ball H311 and the shoulder on valve stem I80.

With the parts in the position of Fig. 2, the exhaust valve 18b is held firmly closed and remains closed during the following operations of the manuals. Referring to Figs. 4, 5 and 6, manual 24 is first moved in a direction to break toggle 22 slightly further outwardly sufiicient to permit manual 23 to move toggle 2| over dead-center to break inwardly. The total effect observed in Fig. 4 is to tilt the equalizer bar 26 While maintaining the valves in casing ill in their fluid supply position with the exhaust port fully closed. In other words, the retrograde movement of toggle 22 is compensated for by the advancing'movemerit of toggle 2!. In Fig. 5 toggle 2| is broken inwardly sufficient to permit toggle 22 to pass over center to an inwardly breaking position While maintaining the valve parts in casing l8 in the same position as in FigJl. The movement of toggle 2| is limited by stop 29. Here the equalizer bar 20 is tilted slightly in the opposite direction but the total advancing efiect of toggles 2| and 22 on the pin l9 remains constant. In Fig. 6 both toggles have broken over center inwardly. The inward movement of toggle 22 is limited by stop 29. Now the manuals maybe released and the toggles will return to an equalized position with the two toggles breaking inwardly an equal amount'and spaced apart properly by the stop means 30. Toggle 2| will move away from stop 29 slightly at this time. The manuals and toggles will remain in the position of Fig. 6 and are positively held there due to the pressure of the fluid supply on the valve parts in casing l8 as previously described because the toggles cannot break over center when under the influence of this pressure. When it is desired to open the press the manuals are returned to the position of Fig. 1 to exhaust motor i5, permitting spring IE to elevate the head.

The stop means 26 is arranged to guide and compel the proper operation of the manuals as previously described, although it will be under- Stood that their manipulation might be performed without this stop 26. As previously pointed out, the position of stop 28 is controlled by rod 21 and the engagement of collar 27b by the bracket No as toggle t4 straightens during the closing of the press. By the proper adjusment of cellar 2th, the stop 2% may be moved relative to the manuals through the various positions shown in Fi s. 3, '7 and 8. In moving from the position of Figs. 2 and 3 to that'of Figsf l and '7, manual 24 has been moved to cause toggle 22 to break slightly farther outwardly by the elevated cam portion 3| on stop 25, At the same time manual 23 is guided to break toggle 2| inwardly by the indented cam portion 32. The manual movement illustrated in Fig. 5 is guided by shoulders 33 and 34 respectively on stop 26. Shoulder 33 permits manual 23 to move inwardly before shoulder 34 permits manual '24 to move inwardly. When both manuals reach the position of Figs. 6 and 8, the stop means 28 is entirely withdrawn and is no longer necessary as the stop means 3|] controls the final position of the manuals.

It will be noted that the manuals and their associated toggles 2| and 22 are'moved from the position of Fig; 2 to the final position of Fig. 6 without at any time permitting an opening of the exhaust valve i812 and yet each of the toggles 2| and 22 has meanwhile passed over a dead-center. All'of the p'arts'are rigidly mounted, none of them are yielding and the parts in their final position hold the'va'lve in a firmly closed efficient fluid supply position under theinfluen ce solely of is accomplished by maintaining substantially constant the combined advancing effect of toggles 2| and 22 acting through equalizer bar 25, that is to say, the combined breaking of the toggles is such as to always maintain the exhaust port |8b tightly closed by the shoulder on the valve stem I82).

What We claim is:

1. In a pressing machine having a frame, having coacting relatively movable pressing members, having fluid actuated power means for causing said relative movement, and having a pressure fluid supply for said power means, control means for said fluid supply comprising rigid valve p-artsrigidly mounted on said frame, said valve parts being so arranged that said fluid supply normally tends to move said parts to fluid cut-01f "position, an equalizer bar, a member operatively connected with said bar intermediate its ends for moving said valve parts to fluid sup- 'ply position, two toggles connected between said 'bar and said frame, one'to each end of said bar and adapted when both are short of central straightened toggle position to hold said valve parts firmly in fluid supply position, manual means for actuating said toggles, stop means for limiting the movement of said toggles beyond central position on one side thereof, and said toggles and equalizing bar and last named n1emher being non-yielding.

2. Control means for a pressing machine as in claim 1, including guide means for compelling toggle operation, from a position with both toggl'es breaking outwardly and holding said valve parts in fluid supply position, to first break one toggle outwardly as the other toggle is moved over center to position breaking inwardly, then to break said other toggle further inwardly as said one toggle is moved over center to position breaking inwardly, and means to limit the inward breaking of said toggles.

3. Control means fora pressing machine as in claim 1, including guide means for compelling toggle operation, from a position with both toggles breaking to one side of central position and holding said valve parts in fluid supply position, to first break one toggle further to said one side of center as the other toggle is moved over center, then to break said other toggle further to the other side of center as said one toggle is moved over center, and means to limit the combined breaking of said toggles to the other side of center to a position corresponding to efficient fluid supply position of said valve parts.

4. In a pressing machine having a frame, 00-

acting relatively movable pressing members, fluid actuated, power means for relatively moving them,"and a fluid pressure supply therefor, control means'for saidsupply, comprising valve parts mounted on the frame-and having a normal tendency to move to fluid'cut-oif position, an equalizer bar, operating means'for said valve parts actuated thereby, two "toggles connected one to each end of "said bar, each thereof having means for manually operating it, said toggles being movable toward each other to over-straightened positions, said toggles when in predetermined over-straigh ened positions being adapted to hold said valve parts in fluid supply position, and stop means movable between said'toggles in the direction of toggle movement and forming an. abutment between them to'limit their relative movement to wardeach other to said predetermined positions.

5. Ina 'pressing machine having a frame, coac'ting "relatively movable pressing "members, fluid actuated power means for relatively moving them, and a fluid pressure supply therefor, control means for said supply, comprising valve parts mounted on the frame and having a normal tendency to move to fluid cut-off position, an equalizer bar, operating means for said valve parts actuated thereby, two toggles connected one to each end of said bar, each thereof having means for manually operating it, said valve parts, bar and toggles being rigidly constructed and mounted whereby predetermined breaking of said toggles outwardly or inwardly holds said valve parts in supply position, a stop controlling movement of said toggles and having surfaces engaging said toggles to compel sufiicient outward breaking of one toggle while the other toggle is moved over center to break inwardly and to compel sufl'icient inward breaking of said other toggle while said one toggle is moved over center to break inwardly, and means limiting said toggles to said predetermined inwardly breaking position.

6. In a pressing machine having a frame, having coacting relatively movable pressing members, having fluid actuated power means for relatively moving said members, and having a pressure fluid supply for said power means, control means for said supply comprising rigid valve parts rigidly mounted on said frame and normally in fluid cut-off position, a rigid equalizer bar having intermediate its ends a rigid operative connection with said valve parts, two toggles constructed of rigid links and connected between said bar and said frame, one to each end of said bar, manual means for operating said toggles, said toggles having positions short of straightened position adapted to hold said valve parts firmly in supply position, stop means removable by movement of said pressing members to a safe-closed position for limiting movement of said toggles to said short-of-straightened position, said toggles being movable toward each other to over-straightened positions when said stop means is removed, and stop means limiting the relative approach of said toggles in over-straightened position to a position where said valve parts are firmly held in fluid supply position.

GEORGE S. BALDWIN. WILLIAM G. MAU. 

